1. Field of the Invention
The present invention relates to a structure of supporting an image bearing member, and more particularly to a structure of supporting the image bearing member of an image bearing unit in an image forming apparatus, in which the image bearing member is supported, at opposite sides thereof, by a pair of side plates formed at the housing of the image bearing unit, and in which a grid electrode for a corona discharger is installed between the side plates.
2. Description of the Related Art
In an image forming apparatus such as a copying machine, a laser beam printer or the like, there has been proposed one having an image bearing unit in which an image bearing member such as a photoreceptor drum or the like is rotatably held in the housing of the image bearing unit. In such an image forming apparatus having the image bearing unit above-mentioned, upon completion of a predetermined amount of image forming operation, the image bearing unit can be removed from the main body of the image forming apparatus and replaced with a new image bearing unit. This advantageously facilitates the mounting of a new image bearing unit.
As the image bearing unit of the type above-mentioned, the following arrangement has been proposed. That is, an image bearing member is interposed between a pair of side plates formed at the housing of the image bearing unit with predetermined gaps formed between the image bearing member and the side plates, and shafts inwardly projecting from the side plates are inserted in and passed through flange portions of the image bearing member at opposite sides thereof so that the image bearing member is rotatably supported. Further, a grid electrode of the scorotron type for a corona discharger is installed between the pair of side plates with a predetermined tension applied to the grid electrode.
In the image bearing unit having the arrangement above-mentioned, a structure of supporting the image bearing member is arranged such that the shafts inwardly projecting from the side plates are inserted in and passed through the flange portions of the image bearing member. Accordingly, the tension applied to the grid electrode may cause the side plates to be inwardly deformed and come in slide contact with opposite sides of the image bearing member. This disadvantageously increases the driving torque of the image bearing member and generates noise.
In view of the problems above-mentioned, the present invention is proposed with the object of providing a structure of supporting an image bearing member which prevents a pair of side plates holding the image bearing member from being inwardly deformed, thus preventing an increase in the driving torque of the image bearing member, as well as generation of noise.